Method for sending and receiving control information, apparatus and communication system

ABSTRACT

The present invention provides a method for sending and receiving control information, an apparatus and a communication system. The method for sending control information includes: setting respective control bits in a downlink control information (DCI) format to generate control information applied by a network side to a terminal, wherein indication information indicating whether to swap a corresponding relationship between a transmission block and a codeword is not carried in a control bit in the DCI format, if a dedicated demodulation reference signal used to demodulate data is preconfigured by the network side for the terminal and respective codewords correspond to the same number of layers; and the indication information is carried in a control bit in the DCI format, if the dedicated demodulation reference signal used to demodulate data is not preconfigured by the network side for the terminal; and sending the generated control information to the terminal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/366,961, filed on Dec. 1, 2016, which is a continuation of patentapplication Ser. No. 14/952,739, filed on Nov. 25, 2015, now U.S. Pat.No. 9,544,894, which is a continuation of U.S. patent application Ser.No. 14/810,951, filed on Jul. 28, 2015, now U.S. Pat. No. 9,220,097,which is a continuation of U.S. patent application Ser. No. 13/435,844,filed on Mar. 30, 2012, now U.S. Pat. No. 9,124,411, which is acontinuation of International Application No. PCT/CN2010/077480, filedon Sep. 29, 2010, which claims priority to Chinese Patent ApplicationNo. 200910204963.2, filed on Sep. 30, 2009. The afore-mentioned patentapplication and patents are hereby incorporated by reference in theirentireties.

FIELD OF THE INVENTION

The present invention relates to the field of communicationtechnologies, and in particular, to a method for sending and receivingcontrol information, an apparatus and a communication system.

BACKGROUND OF THE INVENTION

In a Long Term Evolved (Long Term Evolved, abbreviated as LTE) systemput forward by the Third Generation Partnership Project (ThirdGeneration Partnership Project, abbreviated as 3GPP) organization,downlink transmission channels mainly include: physical downlink controlchannel (Physical downlink control channel, abbreviated as PDCCH) andphysical downlink shared channel (Physical downlink shared channel,abbreviated as PDSCH), which are used to transmit downlink controlinformation (Downlink control information, abbreviated as DCI) anddownlink data respectively. In an LTE Rel.8 system, the downlink datamay be transmitted by using different transmission modes. Eachtransmission mode may include two DCI formats (Format). In the DCIformat, each control bit may indicate control information required by aPDSCH data transmission scheme under a specific transmission mode. Anetwork side configures a specific data transmission mode for eachterminal in a semi-static manner. Under a specific transmission mode,each control bit of the DCI format is configured dynamically so that thecontrol information required by the PDSCH data transmission scheme isindicated to a user. The terminal blindly detects each control bit ofthe two DCI formats and obtains the control information required by thePDSCH data transmission scheme of the terminal.

In the DCI format defined by the LTE Rel.8 system, the DCI format 2 andDCI format 2A support a transmission control indication of two codewords(Codeword, abbreviated as CW). Control bits in the transmission controlindication include: a transmission control bit of a transmission block(Transmission Block, abbreviated as TB), and a control bit of indicationinformation indicating whether to swap a corresponding relationshipbetween the transmission block and the codeword (namely a “TB to CW swapflag” control bit), and so on. Transmission control bits of eachtransmission block includes: a modulation and coding scheme (Modulationand Coding Scheme, abbreviated as MCS) indication bit, a new dataindicator (New data indicator, NDI) bit, and a redundancy version(Redundancy version, abbreviated as RV) indication bit. The network sidecorrespondingly indicates the control information of the twotransmission blocks in the foregoing control bits. The terminal detectseach control bit in the DCI format to determine the control informationof the current PDSCH data transmission.

In the process of implementing embodiments of the present invention, theinventor finds that in the prior art: Efficiency of using the controlbits is improper in a frame structure that supports transmission of twocodewords, therefore a technical defect that efficiency of using anoverhead required for transmitting control information is low exists.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a method for sending andreceiving control information, an apparatus and a communication system,which are used to improve efficiency of using an overhead required fortransmitting control information.

An embodiment of the present invention provides a method for sendingcontrol information, where the method includes:

setting respective control bits in a downlink control information (DCI)format to generate control information applied by a network side to aterminal, wherein indication information indicating whether to swap acorresponding relationship between a transmission block and a codewordis not carried in a control bit in the DCI format, if a dedicateddemodulation reference signal used to demodulate data is preconfiguredby the network side for the terminal and respective codewords correspondto the same number of layers; and the indication information indicatingwhether to swap the corresponding relationship between the transmissionblock and the codeword is carried in a control bit in the DCI format, ifthe dedicated demodulation reference signal used to demodulate data isnot preconfigured by the network side for the terminal; and

sending the generated control information to the terminal.

An embodiment of the present invention provides a method for receivingcontrol information, where the method includes:

receiving control information sent by a network side; and

obtaining control bits in a downlink control information (DCI) formatgenerating the control information applied by the network side to aterminal, wherein indication information indicating whether to swap acorresponding relationship between a transmission block and a codewordis not carried in a control bit in the DCI format, if a dedicateddemodulation reference signal used to demodulate data is preconfiguredby the network side for the terminal and respective codewords correspondto the same number of layers; and the indication information indicatingwhether to swap the corresponding relationship between the transmissionblock and the codeword is carried in a control bit in the DCI format, ifa dedicated demodulation reference signal used to demodulate data is notpreconfigured by the network side for the terminal.

An embodiment of the present invention provides a network side device,where the network side device includes:

a control information generating module, configured to set respectivecontrol bits in a downlink control information (DCI) format to generatecontrol information applied by a network side to a terminal, whereinindication information indicating whether to swap a correspondingrelationship between a transmission block and a codeword is not carriedin a control bit in the DCI format, if a dedicated demodulationreference signal used to demodulate data is preconfigured by the networkside for the terminal and respective codewords correspond to the samenumber of layers; and the indication information indicating whether toswap the corresponding relationship between the transmission block andthe codeword is carried in a control bit in the DCI format, if thededicated demodulation reference signal used to demodulate data is notpreconfigured by the network side for the terminal; and

a control information sending module, configured to send the generatedcontrol information to the terminal.

An embodiment of the present invention provides a terminal side device,where the terminal side device includes:

a control information receiving module, configured to receive controlinformation sent by a network side; and

a control bit resolving module, configured to obtain control bits in adownlink control information (DCI) format generating the controlinformation applied by the network side to a terminal, whereinindication information indicating whether to swap a correspondingrelationship between a transmission block and a codeword is not carriedin a control bit in the DCI format, if a dedicated demodulationreference signal used to demodulate data is preconfigured by the networkside for the terminal and respective codewords correspond to the samenumber of layers; and the indication information indicating whether toswap the corresponding relationship between the transmission block andthe codeword is carried in a control bit in the DCI format, if adedicated demodulation reference signal used to demodulate data is notpreconfigured by the network side for the terminal.

In the embodiments of the present invention, the network side deviceextends or changes functions of some control bits in the DCI format ofthe control information, so as to improve efficiency of using a resourceoverhead occupied by the control bits in the DCI format of the controlinformation, and improve the efficiency of using the overhead requiredfor transmitting the control information.

BRIEF DESCRIPTION OF THE DRAWINGS

To make the technical solutions according to the embodiments of thepresent invention or in the prior art clearer, the following outlinesaccompanying drawings involved in the description of the embodiments orthe prior art. Apparently, the accompanying drawings outlined below aremerely some embodiments of the present invention, and persons ofordinary skill in the art may further obtain other drawings from theseaccompanying drawings without making creative efforts.

FIG. 1a is a flowchart of a method for sending control informationaccording to a first embodiment of the present invention;

FIG. 1b is a flowchart of a method for receiving control informationaccording to a second embodiment of the present invention;

FIG. 2a is a flowchart of a method for sending control informationaccording to a third embodiment of the present invention;

FIG. 2b is a flowchart of a method for receiving control informationaccording to a fourth embodiment of the present invention;

FIG. 3 is a schematic diagram of some control bits in a DCI format thatsupports transmission of two codewords in a comparative instanceaccording to the present invention;

FIG. 4a is a flowchart of a method for sending and receiving controlinformation according to a fifth embodiment of the present invention;

FIG. 4b is a schematic diagram of some control bits in a DCI format thatsupports transmission of two codewords according to an embodiment of thepresent invention;

FIG. 5a is a flowchart of a method for sending and receiving controlinformation according to a sixth embodiment of the present invention;

FIG. 5b is a schematic diagram of some control bits in another DCIformat that supports transmission of two codewords according to anembodiment of the present invention;

FIG. 6 is a flowchart of a method for sending and receiving controlinformation according to a seventh embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a network side deviceaccording to an eighth embodiment of the present invention;

FIG. 8 is a schematic structural diagram of a terminal side deviceaccording to a ninth embodiment of the present invention; and

FIG. 9 is a schematic structural diagram of a communication systemaccording to a tenth embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The technical solutions according to the embodiments of the presentinvention are described clearly and completely in conjunction with theaccompanying drawings in the embodiments of the present invention.Evidently, the embodiments to be described are merely part of ratherthan all of the embodiments of the present invention. Based on theembodiments of the present invention, all other embodiments obtained bythose of ordinary skill in the art without making creative efforts shallfall within the protection scope of the present invention.

FIG. 1a is a flowchart of a method for sending control informationaccording to a first embodiment of the present invention. An executingsubject of this embodiment may be a network side device. As shown inFIG. 1a , the method for sending control information in this embodimentincludes:

Step 11 a: Set respective control bits in a DCI format to generatecontrol information applied by a network side to a terminal, where thecontrol bits in the DCI format include validity indication bits andtransmission control bits, indication information indicating whethertransmission control exercised by the network side on a transmissionblock is valid relative to the terminal is written into the validityindication bits, and the validity indication bits are located outsidethe transmission control bits.

The network side may predetermine a bit among the respective controlbits in the DCI format, and write into this bit the indicationinformation indicating whether transmission control exercised by thenetwork side on a transmission block is valid relative to the terminal.The control bit into which the indication information indicating whetherthe transmission control on the transmission block is valid relative tothe terminal is written is a validity indication bit in the embodimentof the present invention. The validity indication bits are locatedoutside the transmission control bits.

Writing of transmission control indications of one or more transmissionblocks may be supported by the DCI format. The number of bits that needto be occupied by transmission block status indication bits in the DCIformat may be set according to an actual requirement. For example, ifwriting of transmission control indications of multiple transmissionblocks is supported by the DCI format, the number of bits occupied bythe validity indication bits in the DCI format may be less than or equalto the number of transmission blocks of transmission controlindications, the writing of which is supported by the DCI format.Indication information indicating whether transmission control exercisedby the network side on a corresponding transmission block is validrelative to the terminal is written into at least one of the validityindication bits according to a predetermined mapping relationshipbetween each of the validity indication bits and the transmission block.

Step 12 a: Send the generated control information to the terminal.

A terminal side receives the control information and detects therespective control bits in the DCI format of the control information.According to meanings represented by values of the respective controlbits, where the meanings represented by the values of the respectivecontrol bits are negotiated between the terminal side and the networkside, the terminal side may obtain the control information such as theindication indicating whether the transmission control exercised by thenetwork side on the transmission block is valid relative to the currentterminal. The terminal may communicate with the network side accordingto the obtained control information.

In the method for sending control information in this embodiment, thenetwork side predetermines the validity indication bits in the DCIformat of the control information, and writes into the validityindication bits the indication information indicating whether thetransmission control exercised by the network side on the transmissionblock is valid relative to the terminal. In this embodiment, 1 bit isenough for indicating whether the transmission control exercised by thenetwork side on any transmission block is valid relative to theterminal, which saves a resource overhead required to be occupied. Thesaved overhead may be used for transmitting other control information.Therefore, efficiency of using an overhead required for transmitting thecontrol information on the network side is improved. Further, in thisembodiment, the same DCI format may be used to indicate controlinformation corresponding to different downlink data transmissionschemes in different scenarios such as valid transmission control on thetransmission block and invalid transmission control on the transmissionblock. Therefore, a flexible and dynamical swap between differentdownlink data transmission schemes is achieved.

FIG. 1b is a flowchart of a method for receiving control informationaccording to a second embodiment of the present invention. An executingsubject of this embodiment may be a terminal side device. As shown inFIG. 1b , the method for receiving control information in thisembodiment includes:

Step 11 b: Receive control information sent by a network side, wherecontrol bits of a DCI format of the control information include validityindication bits and transmission control bits, and the validityindication bits are located outside the transmission control bits.

Transmission control indications of one or more transmission blocks maybe written into the DCI format. The number of bits that need to beoccupied by the validity indication bits in the DCI format may be set bythe network side according to an actual requirement. For example, iftransmission control indications of multiple transmission blocks arewritten into the DCI format, the number of bits occupied by the validityindication bits in the DCI format may be less than or equal to thenumber of transmission blocks of transmission control information thatmay be written into the DCI format.

Step 12 b: Obtain, from the validity indication bits, indicationinformation indicating whether transmission control exercised by thenetwork side on a transmission block is valid relative to a currentterminal.

The terminal side receives the control information and detectsrespective control bits in the DCI format of the control information.According to meanings represented by values of the respective controlbits, where the meanings represented by the values of the respectivecontrol bits are negotiated between the terminal side and the networkside, the terminal side may obtain the information such as theindication indicating whether the transmission control exercised by thenetwork side on the transmission block is valid relative to the currentterminal. For example, according to a predetermined mapping relationshipbetween each of the validity indication bits and the transmission block,the terminal side obtains indication information carried in each of thevalidity indication bits, and determines, according to the obtainedindication information, whether the transmission control exercised bythe network side on the corresponding transmission block is validrelative to the current terminal.

In the method for receiving control information in this embodiment, bydetecting one bit of the validity indication bits in the DCI format, theterminal side obtains the indication information indicating whether thecontrol exercised by the network side on a transmission block is validrelative to the current terminal, which saves a resource overheadrequired to be occupied by the indication indicating whether thetransmission control on the transmission block is valid. The savedoverhead may be used for transmitting other control information.Therefore, efficiency of using the overhead required for transmittingthe control information on the network side is improved, and efficiencyof obtaining the downlink control information by the terminal side isalso improved. Further, in this embodiment, the same DCI format may beused to obtain control information corresponding to different downlinkdata transmission schemes in different scenarios such as validtransmission control on the transmission block and invalid transmissioncontrol on the transmission block. Therefore, a flexible and dynamicalswap between different downlink data transmission schemes is achieved.

FIG. 2a is a flowchart of a method for sending control informationaccording to a third embodiment of the present invention. An executingsubject of this embodiment may be a network side device. As shown inFIG. 2a , the method for sending control information in this embodimentincludes:

Step 21 a: Set respective control bits in a DCI format to generatecontrol information applied by a network side to a terminal, wherecontrol information other than indication information indicating whetherto swap a corresponding relationship between a transmission block and acodeword is written into a control bit into which the indicationinformation indicating whether to swap a corresponding relationshipbetween a transmission block and a codeword is originally written, andthe control bit is in the DCI format of the control information, if adedicated demodulation reference signal used to demodulate data ispreconfigured by the network side for the terminal and respectivecodewords correspond to the same number of layers.

The other control information includes at least one of the following:indication information indicating whether transmission control exercisedby the network side on the corresponding transmission block is validrelative to the terminal; indication information indicating anorthogonal reference signal occupied by the dedicated demodulationreference signal of the terminal; information indicating locations ofresources such as a time frequency occupied by the dedicateddemodulation reference signal on scheduled resources of the terminal;configuration information about the number of orthogonal frequencydivision multiplexing symbols occupied by physical downlink controlchannels of multiple cells under a coordinated multiple pointstransmission scheme; the number of layers occupied by the terminal;indication information indicating whether current control information isuplink control information or downlink control information; indicationinformation indicating component carriers of carrier aggregation; anduplink feedback scheme indication information or uplink schedulinginformation.

The control bits in the DCI format include a control bit into which theindication information indicating whether to swap a correspondingrelationship between a transmission block and a codeword is written(namely a “TB to CW swap flag” control bit). If a dedicated demodulationreference signal used to demodulate data is preconfigured by the networkside for the terminal, and respective codewords correspond to the samenumber of layers, the indication information indicating whether to swapa corresponding relationship between a transmission block and a codewordis meaningless redundant indication information in a currenttransmission status. Therefore, the control information other than theindication information indicating whether to swap a correspondingrelationship between a transmission block and a codeword may be writteninto the “TB to CW swap flag” control bit.

Step 22 a: Send the generated control information to the terminal.

The terminal side receives the control information and detects therespective control bits in the DCI format of the control information.From the “TB to CW swap flag” control bit, the terminal may obtain thecontrol information other than the information indicating whether toswap the corresponding relationship between the transmission block andthe codeword.

In the method for sending control information in this embodiment, afunction of the “TB to CW swap flag” control bit is determined withreference to the current transmission status of the transmission block.If the indication information indicating whether to swap a correspondingrelationship between a transmission block and a codeword is meaninglessredundant indication information in the current transmission status, thecontrol information other than the information indicating whether toswap the corresponding relationship between the transmission block andthe codeword may be written into the “TB to CW swap flag” control bit,which saves a resource overhead required to be occupied for transmittingother control information, and improves efficiency of using an overheadrequired for transmitting the control information on the network side.

FIG. 2b is a flowchart of a method for receiving control informationaccording to a fourth embodiment of the present invention. An executingsubject of this embodiment may be a terminal side device. As shown inFIG. 2b , the method for receiving control information in thisembodiment includes:

Step 21 b: Receive control information sent by a network side.

The network side sets respective control bits in a DCI format togenerate the control information, and sends the generated controlinformation to the terminal side.

Step 22 b: Obtain control information other than indication informationindicating whether to swap a corresponding relationship between atransmission block and a codeword, from a control bit into which theindication information indicating whether to swap a correspondingrelationship between a transmission block and a codeword is originallywritten, where the control bit is in the DCI format of the controlinformation, if a dedicated demodulation reference signal used todemodulate data is preconfigured by the network side for a currentterminal and respective codewords correspond to the same number oflayers.

The control bits in the DCI format include a control bit into which theindication information indicating whether to swap a correspondingrelationship between a transmission block and a codeword is written(namely a “TB to CW swap flag” control bit). If a dedicated demodulationreference signal used to demodulate data is preconfigured by the networkside for the terminal, and respective codewords correspond to the samenumber of layers, the indication information indicating whether to swapa corresponding relationship between a transmission block and a codewordis meaningless redundant indication information in a currenttransmission status. Therefore, the control information other than theindication information indicating whether to swap a correspondingrelationship between a transmission block and a codeword may be writteninto the “TB to CW swap flag” control bit. By detecting the “TB to CWswap flag” control bit, the current terminal may obtain the controlinformation other than the information indicating whether to swap thecorresponding relationship between the transmission block and thecodeword.

In the method for receiving control information in this embodiment, ifthe indication information indicating whether to swap a correspondingrelationship between a transmission block and a codeword is meaninglessredundant indication information in the current transmission status, afunction of the “TB to CW swap flag” control bit is determined withreference to the current transmission status of the transmission block,and the control information other than the information indicatingwhether to swap a corresponding relationship between a transmissionblock and a codeword is written into the “TB to CW swap flag” controlbit. By detecting the “TB to CW swap flag” control bit, the currentterminal may obtain the control information other than the informationindicating whether to swap a corresponding relationship between atransmission block and a codeword, which saves a resource overheadrequired to be occupied for transmitting other control information, andimproves efficiency of using an overhead required for transmitting thecontrol information on the network side.

FIG. 3 is a schematic diagram of some control bits in a DCI format thatsupports transmission of two codewords in a comparative instanceaccording to the present invention. FIG. 3 only shows some control bitsrelated to a transmission block in the DCI format that supports atransmission control indication of two codewords in an LTE Rel.8 system,for example, some control bits in the DCI format 2 and the DCI format 2Aare defined in the LTE Rel.8 system. Some control bits in the DCIformat, the number of resources occupied by such control bits andfunctions of such control bits shown in FIG. 3 are described as follows:

“HARQ process number”: occupies 3 bits, into which indicationinformation about a Hybrid Automatic Retransmission Request (HARQ)process number is written, and may be called “HARQ process numberindication bit”;

TB1 transmission control bits: occupy 8 bits, into which transmissioncontrol information of a transmission block is written;

TB2 transmission control bits: occupy 8 bits, into which transmissioncontrol information of another transmission block is written; and

“TB to CW swap flag” control bit: occupies 1 bit, into which indicationinformation indicating whether to swap a corresponding relationshipbetween a transmission block and a codeword is written, and may becalled “TB to CW swap indication bit”. It is assumed that two codewordsthat may be mapped to the transmission block are a CW0 and a CW1respectively. By default, a TB1 corresponds to the CW0, and a TB2corresponds to the CW1. If the value of the “TB to CW swap flag” controlbit is 0, it indicates that the corresponding relationship between thetransmission block and the codeword is not swapped. That is, the TB1corresponds to the CW0, and the TB2 corresponds to the CW1. If the valueof the “TB to CW swap flag” control bit is 1, it indicates that thecorresponding relationship between the transmission block and thecodeword is swapped, and in this case, the TB2 corresponds to the CW0,and the TB1 corresponds to the CW1.

The transmission control bits of each transmission block (TB1transmission control bits or TB2 transmission control bits) are dividedinto the following bits:

MCS indication bits: occupy 3 bits, into which indication informationindicating a modulation and coding scheme applied to the datatransmitted in a current transmission block;

NDI indication bit: occupies 1 bit, into which indication informationindicating a type of data transmitted in a current transmission block,for example, indicating whether the data transmitted in the currenttransmission block is new data or retransmitted old data; and

RV indication bits: occupy 2 bits, into which indication informationindicating a redundancy version.

Corresponding control information is written into the foregoing MCSindication bits, NDI indication bit and RV indication bits, which areoriginal transmission control indications of the transmission blockdescribed in the embodiment of the present invention.

In the process of implementing the embodiments of the present invention,the inventor finds that: In the LTE Rel.8 system, certain control bitsare used improperly in the DCI format that supports the transmissioncontrol indication of two codewords, as reflected in the following:

1. Overhead using of TB control bits indicating that a transmissionblock is invalid:

In an LTE Rel.8 system, if data transmitted in a current transmissionblock is unrelated to a terminal, by setting 7 bits included in the MCSindication bits and the NDI indication bit in the transmission controlbits corresponding to the transmission block in the DCI format tospecific values, the network side notifies the terminal thattransmission control exercised by the network side on this transmissionblock is invalid relative to a terminal. For example, if datatransmitted in the current TB2 is unrelated to a terminal, the networkside sets all the 7 bits included in the MCS indication bits and the NDIindication bit among the TB2 control bits to 0, so as to indicate thatthe transmission control currently exercised by the network side on theTB2 is invalid relative to the terminal, and sends the controlinformation that is set according to the DCI format to the terminal. Theterminal receives the control information and detects the respectivecontrol bits in the DCI format of the control information. If adetection result of the terminal indicates that the 7 bits included inthe MCS indication bits and the NDI indication bit in the TB2transmission control bits are all 0, the terminal determines that thedata transmitted in the TB2 are not sent to the terminal, namely,determines that the transmission control exercised by the network sideon the TB2 is invalid relative to the terminal.

It is assumed that, at a specific scheduling time, transmission controlexercised by the network side on a transmission block is valid relativeto a terminal A, but transmission control exercised by the network sideon another transmission block is invalid relative to the terminal A, forexample, in an application scenario that transmission control on the TB1is valid relative to the terminal A, but transmission control on the TB2is invalid relative to the terminal A, the network side in the existingLTE Rel.8 system uses 7 bits (bits occupied by the MCS indication bitsand the RV indication bits) in the TB2 control bits to indicate that thetransmission control exercised by the network side on the TB2 is invalidrelative to the terminal A. Consequently, efficiency of using thecontrol bits is improper at all, and a utilization rate of an overheadof the transmission control information is low. Therefore, the bitsoccupied by the information indicating that transmission control on atransmission block is invalid relative to a terminal in the DCI formatmay be saved, and the saved resource overhead may be used fortransmitting other control information.

2. Resource overhead occupied by the “TB to CW swap flag” control bit:

In the LTE Rel.8 system, if control exercised by the network side on thetwo transmission blocks, the TB1 and the TB2, are both valid relative tothe terminal, the network side uses a “TB to CW swap flag” control bitin the DCI format to indicate control information required by theterminal for demodulating data. Specifically, in the process ofcommunication between the network side and the terminal side, thenetwork side sends the same common reference information to eachterminal, and determines a precoding matrix (Precoding Matrix,abbreviated as PM) used by each terminal. The network side uses aprecoding matrix indicator (PM Indicator, abbreviated as PMI), to notifya corresponding terminal of the precoding matrix used for precoding of auser. The PMI is delivered through a dedicated control bit (not shown inFIG. 3). According to the common reference signal and the received PMIinformation, the terminal determines a channel estimated value requiredfor demodulating the received data.

In the LTE Rel.8 system, the “TB to CW swap flag” control bit is used toindicate whether to swap the corresponding relationship between thetransmission block and the codeword in the case that the transmissioncontrol exercised by the network side on the TB1 and the TB2 are bothvalid relative to a terminal. In an application scenario that thetransmission control is valid on only one transmission block, theindication information written into the “TB to CW swap flag” control bitis actually meaningless. In this application scenario, the resourceoverhead occupied by the “TB to CW swap flag” control bit may be usedfor transmitting other control information.

Besides, with the continuous evolution of an LTE system version, acommunication mode of an LTE system of a higher version such as LTERel.9 or LTE Rel.10 is different in comparison with that of the LTERel.8 system. In a possible implementation mode of the LTE Rel.9 or LTERel.10 system, the network side does not need to indicate whether toswap the corresponding relationship between the transmission block ofthe terminal and the codeword of the terminal, and the resource overheadoccupied by the “TB to CW swap flag” control bit may be used fortransmitting other control information. Specifically, in a possibleimplementation mode of the LTE Rel.9 or LTE Rel.10 system, the networkside determines a dedicated demodulation reference signal for eachterminal, and, according to the dedicated demodulation reference signalcorresponding to the terminal, the terminal may determine a channelestimated value required for demodulating data, and does not need toobtain the PMI information to determine the channel estimated value. Onthe other hand, whether to swap the mapping between the transmissionblock and the codeword may be completed by determining whether to swapprecoding vectors in a precoding matrix corresponding to a layer mappedto each codeword. The network side does not need to indicate theprecoding information to the user in the case that the network sidedetermines the dedicated reference signal for each terminal, andtherefore, the network side does not need to indicate to the userinformation about whether to swap the corresponding relationship betweenthe transmission block and the codeword.

Therefore, if indication information that may be written into certaincontrol bits in the DCI format are meaningless redundant indicationinformation in the current transmission status, such control bits (suchas a PMI dedicated control bit or the “TB to CW swap flag” control bit)may be used for transmitting other control information.

For example, the foregoing other control information may be: indicationinformation indicating an orthogonal reference signal occupied by adedicated demodulation reference signal of the terminal A when the dataof multiple users share the same time-frequency resources and in thecase that their dedicated demodulation reference signals are orthogonal;or information indicating whether a single user occupiescurrently-scheduled time-frequency resources exclusively or multipleusers share the currently-scheduled time-frequency resources;information indicating locations of resources such as a time frequencyoccupied by a dedicated demodulation reference signal on scheduledresources of the terminal A when a load occupied by a dedicateddemodulation reference signal of a user is variable; configurationinformation indicating the number of Orthogonal Frequency DivisionMultiplexing (Orthogonal Frequency Division Multiplexing, abbreviated asOFDM) symbols occupied by PDCCHs of multiple cells during joint sendingfrom multiple cells under a coordinated multiple points (Coordinatedmultiple points, abbreviated as CoMP) transmission scheme; informationindicating the number of layers occupied by the terminal in the casethat the user data is adaptive; information indicating whether thecontrol information of the terminal is uplink or downlink controlinformation when the network side applies the same length of controlbits of the DCI format to the uplink scheduling information of theterminal and the downlink scheduling information of the terminal;indication information indicating component carriers of the terminal inthe case of carrier aggregation; and information indicating an uplinkfeedback scheme of the terminal in the case that the terminal hasmultiple feedback schemes in the corresponding transmission mode, uplinkscheduling information of the terminal when the network side applies thesame length of the control bits of the DCI format to the uplinkscheduling information of the terminal, or control information otherthan the information about the transmission control on the TB2.

It can be known from the foregoing analysis that, in the DCI format thatsupports transmission of control information of two codewords in the LTERel.8 system, the potentiality of enhancing efficiency of using theoverhead occupied by the TB control bit and the “TB to CW swap flag”indication bit is great. Further, by taking the communicationimplementation mode of the LTE system of a higher version such as LTERel.9 or LTE Rel.10 system into consideration, the use of the overheadof the “TB to CW swap flag” indication bit in the DCI format isoptimized to improve efficiency of using the resource overhead occupiedby the transmission control information.

In this embodiment, an optimized setting process of the control bits inthe DCI format may be based on the following principles:

1. Try to support transmission of control information corresponding tomore transmission schemes in a DCI format.

In a possible implementation mode of the LTE Rel.9 or LTE Rel.10 system,it is necessary to improve spectral efficiency by supportingtransmission schemes such as dual-stream beam forming, higher-ordermulti-input multi-output (Multiple-Input Multiple-Out-put, abbreviatedas MIMO), and CoMP. Such transmission schemes are new relative to theLTE Rel.8 system, and can optimize the efficiency of using the overheadresources occupied by the control bits so that the control informationof the most possible transmission schemes may be indicated by one DCIformat. In this way, after the network side indicates the current datatransmission mode in a semi-static manner, the terminal side may obtainthe required control information by detecting the control bits in a DCIformat dynamically, and the network side may swap the controlinformation dynamically to indicate multiple transmission schemes, whichimproves the spectral efficiency.

2. Try to reduce the cost required for upgrading the LTE Rel.8 system.

One of the modes of reducing the cost of upgrading the LTE Rel.8 systemis to reduce the change of the decoding process when the terminalreceives the control information. Therefore, in the process of optimizedsetting of the DCI format of the control information, the DCI formatthat has the same length as that in the existing LTE Rel.8 system ispreferred, and the functions of some control bits need to be extended orchanged on the basis of the existing DCI format to improve theefficiency of using the resource overhead occupied by the control bitsin the DCI format.

Based on the foregoing requirements and principles, in the embodimentsof the present invention, validity indication bits may be set in the DCIformat, where indication information indicating whether the controlexercised by the network side on the transmission block is validrelative to the terminal is written into the validity indication bits.The validity indication bits may be newly-added control bits in anoriginal DCI format, or original control bits in the DCI format, whereindication information written into the original control bits isredundant indication information in the current transmission status. Thevalidity indication bits are located outside the transmission controlbits, and the number of bits occupied by the validity indication bits isless than or equal to the number of transmission blocks of transmissioncontrol indications that may be written into the DCI format. Forexample, if transmission control indications of 2 transmission blocksare written into the DCI format, the validity indication bits may occupy1 or 2 bits. If transmission control exercised by the network side on atransmission block at a specific scheduling time is invalid relative tothe current terminal, the 1 bit of overhead occupied by the “TB to CWswap flag” control bit and the 8 bits occupied by the transmissioncontrol bits corresponding to the transmission blocks under invalidtransmission control may be used for carrying other control information.Besides, if the terminal in the communication system uses the dedicateddemodulation signal to demodulate data and respective codewordscorrespond to the same number of layers, the terminal side does not needto acquire the indication information indicating whether to swap thecorresponding relationship between the transmission block and thecodeword, and the bit overhead occupied by the “TB to CW swap flag”control bits may be used for transmitting other control information.

In the embodiment of the present invention, the network side deviceextends or changes the functions of some control bits in the DCI formatof the control information, and uses the control bits in the DCI format2 and format 2A of the LTE Rel.8 system to fulfill transmission controlin new data transmission schemes of the upgraded systems such as LTERel.9 and LTE Rel10. Any one of such DCI formats may be used to supporttransmission control of a variety of data transmission schemes, whichfacilitates flexible and dynamical swap between different downlink datatransmission schemes.

By taking a DCI format that supports a transmission control indicationof two codewords as an example, implementation modes for improving theefficiency of using a resource overhead occupied by control informationtransmission according to the present invention are described.

FIG. 4a is a flowchart of a method for sending and receiving controlinformation according to a fifth embodiment of the present invention.FIG. 4b is a schematic diagram of some control bits in a DCI format thatsupports transmission of two codewords according to an embodiment of thepresent invention. In this embodiment, it is assumed that a validityindication bit occupies 1 bit, which is expressed as S2 and used tocarry indication information indicating whether transmission controlexercised by a network side on a specific transmission block such as aTB2 is valid relative to a terminal. As shown in FIG. 4a and FIG. 4b ,the method for sending and receiving control information in thisembodiment includes:

Step 41: A network side sets a value of an S2 in a DCI format at aspecific scheduling time to indicate whether transmission controlexercised on a TB2 is valid relative to a terminal at a currentscheduling time: If the transmission control on the TB2 is validrelative to the terminal, respective bits occupied by transmissioncontrol bits of the TB2 are used to carry an original transmissioncontrol indication of the TB2; if the transmission control exercised bythe network side on the TB2 is invalid relative to the terminal, part orall of bits occupied by transmission control bits of the TB2 are used tocarry control information other than an original transmission controlindication of the TB2.

Meanings of values of the S2 may be pre-negotiated between the networkside and the terminal side. For example,

S2=0: Transmission control on the TB2 is invalid relative to theterminal; and

S2=1: Transmission control on the TB2 is valid relative to the terminal.

It is assumed that the network side schedules two transmission blocks, aTB1 and the TB2, for a terminal A at a specific scheduling time totransmit data, an instance of setting the control bits in the DCI formatshown in FIG. 4b may be:

S2=1 is used to indicate that the transmission control on the TB2 isvalid relative to the terminal.

The MCS, NDI, and RV indication bits in the TB1 control bits are used toindicate the transmission control information on the TB1; and

The MCS, NDI, and RV indication bits in the TB2 control bits are used toindicate the transmission control information on the TB2.

It is assumed that the network side schedules one transmission block TB1for the terminal A at a specific scheduling time to transmit data, aninstance of setting the control bit in the DCI format shown in FIG. 4bmay be:

S2=0 is used to indicate that the transmission control on the TB2 isinvalid relative to the terminal.

The MCS, NDI, and RV indication bits in the TB1 control bits are used toindicate the transmission control information on the TB1.

The MCS, NDI, and RV indication bits in the TB2 control bits are used toindicate other control information.

For example, the foregoing other control information may be: indicationinformation indicating an orthogonal reference signal occupied by adedicated demodulation reference signal of the terminal A when the dataof multiple users share the same time-frequency resources and in thecase that their dedicated demodulation reference signals are orthogonal;or information indicating whether a single user occupiescurrently-scheduled time-frequency resources exclusively or multipleusers share the currently-scheduled time-frequency resources;information indicating locations of resources such as a time frequencyoccupied by a dedicated demodulation reference signal on scheduledresources of the terminal A when a load occupied by a dedicateddemodulation reference signal of a user is variable; configurationinformation indicating the number of OFDM symbols occupied by the PDCCHsof multiple cells during joint sending from multiple cells under a CoMPtransmission scheme; information indicating the number of layersoccupied by the terminal A in the case that the user data is adaptive;information indicating whether the control information of the terminal Ais uplink or downlink control information when the network side appliesthe same length of control bits of the DCI format to the uplinkscheduling information of the terminal and the downlink schedulinginformation of the terminal; indication information indicating componentcarriers of the terminal A in the case of carrier aggregation; andinformation indicating an uplink feedback scheme of the terminal A inthe case that the terminal has multiple feedback schemes in thecorresponding transmission mode, uplink scheduling information of theterminal when the network side applies the same length of the controlbits of the DCI format to the uplink scheduling information of theterminal A, or control information other than the information about thetransmission control on the TB2.

In this step, if the terminal side in the communication system uses thededicated demodulation signal to obtain the channel estimated valuerequired for demodulating data, and respective codewords correspond tothe same number of layers, the 1 bit of overhead occupied by the “TB toCW swap flag” indication bit shown in FIG. 3 may also be used to carrythe indication information indicating whether the transmission controlon the transmission block is valid or invalid relative to the terminal.Persons skilled in the art understand that in this scenario, the 1 bitof overhead occupied by the “TB to CW swap flag” control bit may also beused for carrying the foregoing other control information; or, if thetransmission control on the TB2 is invalid in this step, the 1 bit ofoverhead occupied by the “TB to CW swap flag” control bit shown in FIG.3 may be used for carrying the foregoing other control information.

Step 42: The network side sets the control information by using theforegoing DCI format, and sends the control information to the terminalA.

Step 43: The terminal A receives the control information sent by thenetwork side.

Step 44: The terminal A detects respective control bits in the DCIformat of the control information, and obtains, at the S2, theindication information indicating whether control exercised by thenetwork side on the transmission block is valid relative to theterminal. The terminal A may determine, according to the indicationinformation in the S2, a type of the information carried in thetransmission control bits of the TB2: If S2=1, it is determined thatrespective bits occupied by the TB2 control bits carry the originaltransmission control indication of the TB2; if S2=0, it is determinedthat part or all of the bits occupied by the TB2 control bits carrycontrol information other than the original transmission controlindication of the TB2.

In the method for sending and receiving control information in thisembodiment, the network side predetermines the validity indication bitsin the DCI format of the control information. If the transmissioncontrol exercised by the network side on the TB2 is invalid relative tothe terminal at a specific scheduling time, 1 bit in this embodiment isenough for indicating whether the transmission control on the TB2 isvalid. All or part of the bits occupied by the TB2 transmission controlbits may be used for transmitting control information other than theinformation about the transmission control on the TB2, which improvesthe efficiency of using the resource overhead required for transmittingthe control information. Further, if dedicated demodulation referenceinformation used for determining the channel estimated value requiredfor demodulating data is pre-allocated to the terminal side, andrespective codewords correspond to the same number of layers, controlinformation other than the information indicating whether to swap acorresponding relationship between a transmission block and a codewordis written into an original “TB to CW swap flag” control bit in the DCIformat, which saves the resource overhead required for transmitting thecontrol information. If, in this scenario, the original “TB to CW swapflag” control bit in the DCI format is used to indicate whether thetransmission control exercised by the network side on the TB2 is validrelative to the terminal, it is conducive to keeping the length of theoriginal DCI format in the LTE Rel.8 system unchanged and reducing thecost of upgrading the LTE Rel.8 system.

FIG. 5a is a flowchart of a method for sending and receiving controlinformation according to a sixth embodiment of the present invention.FIG. 5b is a schematic diagram of some control bits in another DCIformat that supports transmission of two codewords according to anembodiment of the present invention. A frame structure shown in FIG. 5bdiffers from that shown in FIG. 4b in that: In the frame structure shownin FIG. 5b , transmission block status indication bits occupy 2 bits.The two bits are expressed as S1 and S2 respectively, and each bit isused to indicate whether transmission control exercised by the networkside on a transmission block is valid relative to the terminal. As shownin FIG. 5a and FIG. 5b , the method for sending and receiving controlinformation in this embodiment includes:

Step 51: A network side sets values of an S1 and an S2 at a specificscheduling time to indicate whether transmission control exercised bythe network side on a TB1 and a TB2 is valid relative to a terminal at acurrent scheduling time respectively: If the transmission control onboth the TB1 and the TB2 is valid relative to the terminal, respectivebits occupied by control bits of the TB1 and the TB2 are used to carryan original transmission control indication of the TB1 and an originaltransmission control indication of the TB2 respectively; if thetransmission control exercised on either the TB1 or the TB2 is invalid,part or all of the bits occupied by transmission control bits of atransmission block under invalid transmission control are used to carrycontrol information other than an original transmission controlindication of this transmission block.

Meanings of values of the S1 and the S2 may be pre-negotiated betweenthe network side and the terminal side. For example,

S1=0: Transmission control on the TB1 is invalid relative to theterminal;

S1=1: Transmission control on the TB1 is valid relative to the terminal;

S2=0: Transmission control on the TB2 is invalid relative to theterminal; and

S2=1: Transmission control on the TB2 is valid relative to the terminal.

If the network side schedules two transmission blocks, the TB1 and theTB2, for a terminal A at a specific scheduling time to transmit data,namely, S1=1 and S2=1, the MCS, NDI, and RV indication bits of TB1control bits are used to indicate the transmission control informationon the TB1; and the MCS, NDI, and RV indication bits of TB2 control bitsare used to indicate the transmission control information on the TB2.

If the network side schedules one transmission block, the TB1 or theTB2, for a terminal A at a specific scheduling time to transmit data,for example, transmit data over the transmission block TB1, S1=1 andS2=0. In this case, the MCS, NDI, and RV indication bits of TB1 controlbits are used to carry an original transmission control indication ofthe TB1, and part or all of the bits occupied by the MCS, NDI, and RVindication bits of TB2 control bits are used to transmit controlinformation other than an original transmission control indication ofthe TB2; or, if S1=0 and S2=1, part or all of bits occupied by the MCS,NDI, and RV indication bits of TB1 control bits are used to carrycontrol information other than an original transmission controlindication of the TB1, and the MCS, NDI, and RV indication bits of TB2control bits are used to carry an original transmission controlindication of the TB2.

For example, the foregoing other control information may be: indicationinformation indicating an orthogonal reference signal occupied by adedicated demodulation reference signal of the terminal A when the dataof multiple users share the same time-frequency resources and in thecase that their dedicated demodulation reference signals are orthogonal;or information indicating whether a single user occupiescurrently-scheduled time-frequency resources exclusively or multipleusers share the currently-scheduled time-frequency resources;information indicating locations of resources such as a time frequencyoccupied by a dedicated demodulation reference signal on scheduledresources of the terminal A when a load occupied by a dedicateddemodulation reference signal of a user is variable; configurationinformation indicating the number of OFDM symbols occupied by the PDCCHsof multiple cells during joint sending from multiple cells under a CoMPtransmission scheme; information indicating the number of layersoccupied by the terminal A in the case that the user data is adaptive;information indicating whether the control information of the terminal Ais uplink or downlink control information when the network side appliesthe same length of control bits of the DCI format to the uplinkscheduling information of the terminal and the downlink schedulinginformation of the terminal; indication information indicating componentcarriers of the terminal A in the case of carrier aggregation; andinformation indicating an uplink feedback scheme of the terminal A inthe case that the terminal has multiple feedback schemes in thecorresponding transmission mode, uplink scheduling information of theterminal when the network side applies the same length of the controlbits of the DCI format to the uplink scheduling information of theterminal A, or other control information except the originaltransmission control indication of this transmission block.

In this step, if the terminal side in the communication system uses thededicated demodulation signal to obtain the channel estimated valuerequired for demodulating data, and respective codewords correspond tothe same number of layers, the 1 bit of overhead occupied by the “TB toCW swap flag” control bit shown in FIG. 3 may also be used to carry theindication information indicating whether the transmission control on atransmission block is valid or invalid. Persons skilled in the artunderstand that in this scenario, the 1 bit of overhead occupied by the“TB to CW swap flag” control bit may also be used for carrying theforegoing other control information; or, if the transmission controlexercised by the network side on either the TB1 or the TB2 is invalidrelative to the terminal A in this step, the 1 bit of overhead occupiedby the “TB to CW swap flag” control bit shown in FIG. 3 may be used forcarrying the foregoing other control information.

Step 52: The network side sets the control information by using theforegoing DCI format, and sends the control information to the terminalA.

Step 53: The terminal A receives the control information sent by thenetwork side.

Step 54: The terminal A detects respective control bits in the DCIformat of the control information, and obtains, at the S1 and the S2respectively, the indication information indicating whether controlexercised by the network side on the TB1 and the TB2 is valid relativeto the terminal. According to the information obtained at the S1 and theS2 respectively, the terminal A determines types of the informationcarried in the TB1 transmission control bits and the TB2 transmissioncontrol bits separately: If 51=1, it is determined that the respectivebits occupied by the TB1 transmission control bits carry the originaltransmission control indication of the TB1; if S1=0, it is determinedthat the control information carried in part or all of the bits occupiedby the TB1 transmission control bits is control information other thanthe original transmission control indication of the TB1; if S2=1, it isdetermined that the respective bits occupied by the TB2 control bitscarry the original transmission control indication of the TB2; if S2=0,it is determined that the control information carried in part or all ofthe bits occupied by the TB2 transmission control bits is controlinformation other than the original transmission control indication ofthe TB2.

The method for sending and receiving control information in thisembodiment enriches indication modes of indicating whether thetransmission control exercised by the network side on each transmissionblock is valid relative to the terminal in the DCI format on the basisof accomplishing the technical effects similar to those of FIG. 4a , andimproves the flexibility of transmitting the indication informationindicating whether the transmission control on the transmission block isvalid.

FIG. 6 is a flowchart of a method for sending and receiving controlinformation according to a seventh embodiment of the present invention.An application scenario in this embodiment is: A network side schedules2 transmission blocks, a TB1 and a TB2, for a terminal A at a previousscheduling time, but changes a scheduling policy on the terminal A at acurrent scheduling time as: scheduling one transmission block, the TB1or the TB2, to transmit data (in this embodiment, an example that thenetwork side schedules the TB1 for the terminal A is taken). In thisembodiment, the DCI format shown in FIG. 4b may be used to deliver thecontrol information. Specifically, the method for sending and receivingcontrol information in this embodiment includes:

Step 61: A network side sets a value of an S2 in a DCI format to 0 toindicate that transmission control exercised by the network side on aTB2 at a current scheduling time is invalid relative to a terminal A.Control information written into NDI indication bits in TB1 transmissioncontrol bits indicates whether data currently transmitted by a TB1 isinitially-transmitted new data or retransmitted old data. If the controlinformation written into the NDI indication bits in the TB1 transmissioncontrol bits indicates that the data currently transmitted by the TB1 isthe retransmitted old data, TB2 transmission control bits, into which anindication indicating whether the old data currently transmitted by theTB1 is retransmitted old data sent by the TB2 at a previous schedulingtime is written, are selected.

If the control information is generated by setting the DCI format shownin FIG. 4b , because the validity indication bit in the DCI formatoccupies only 1 bit, the validity indication bit can only be used tocarry an indication indicating whether transmission control exercised bythe network side on either the TB1 or the TB2 is valid relative to theterminal. Therefore, in the application scenario of this embodiment, ifthe network side schedules 2 transmission blocks, the TB1 and the TB2,for the terminal A to transmit data at the previous scheduling time, butchanges the scheduling policy on the terminal A at the currentscheduling time as: scheduling one transmission block TB1 to transmitdata, and, if the transmission control information of the TB1 shows thata current transmission status is retransmission of old data, theterminal A may be unable to distinguish whether the retransmission ofold data is intended for the TB1 or the TB2 at the previous time, whichis unfavorable to correct reception of data by the terminal A. For thisapplication scenario, in this embodiment, an indication of atransmission block to which the currently-transmitted old data belongs,where the transmission block is controlled by a TB1 transmission controlbits, is written into the TB2 transmission control bits. In this way,the terminal is enabled to acquire whether the old data currentlytransmitted by the TB1 is retransmission of old data of the TB1 orretransmission of old data of the TB2, and thus the data can be receivedcorrectly.

Because the control exercised by the network side on the TB2 is invalidat the current scheduling time relative to terminal A, controlinformation other than the information about the transmission control onthe TB2 may be written into the TB2 transmission control bits.Specifically, the TB1 transmission control bits indicate whether thecurrently-transmitted old data is retransmission of the old data sent bythe TB2 at the previous scheduling time. Information may be written intoany bit among the TB2 transmission control bits according to thenegotiation between the network side and the terminal A, for example,may be written into an NDI indication bit, an MCS indication bit, an RVindication bit that are in the TB2 transmission control bits, or,another indication bit in the DCI format.

Step 62: The network side sets the control information by using theforegoing DCI format, and sends the control information to the terminalA.

Step 63: The terminal A receives the control information sent by thenetwork side.

Step 64: The terminal A detects respective control bits in the DCIformat of the control information. According to a detection result ofthe S2, the terminal A determines that control information carried inbits occupied by the TB2 control bits is control information other thanan original transmission control indication of the TB2; according tocontrol information written into the NDI indication bits in the TB1transmission control bits, the terminal A determines whether datacurrently transmitted by the TB1 is new data or retransmitted old data;if the data is retransmitted old data, the terminal A obtains, from bitsthat are pre-negotiated with the network side in the TB2 transmissioncontrol bits, indication information indicating whether the old datacurrently transmitted by the TB1 is retransmission of the old data sentby the TB2 at the previous scheduling time.

By detecting the TB2 transmission control bits, the terminal A mayobtain an indication indicating whether the old data currentlytransmitted by a TB1 transmission control indication is retransmissionof the old data sent by the TB2 at the previous scheduling time.Specifically, the terminal A may obtain that the old data currentlytransmitted by the TB1 transmission control indication is retransmissionof the old data sent by the TB2 at the previous scheduling time, or thatthe old data currently transmitted by the TB1 transmission controlindication is not retransmission of the old data sent by the TB2 at theprevious scheduling time. If the terminal A obtains that the old datacurrently transmitted by the TB1 transmission control indication is notretransmission of the old data sent by the TB2 at the previousscheduling time, it is determined that the old data currentlytransmitted by the TB1 transmission control indication is retransmissionof the old data sent by the TB1 at the previous scheduling time.

On the basis of accomplishing the technical effects similar to those ofFIG. 4a , the method for sending and receiving control information inthis embodiment delivers validity indication information; when the datacurrently transmitted by the transmission block under valid transmissioncontrol is old data, a transmission control bit of the transmissionblock under invalid transmission control indicates a transmission blockto which the old data belongs, and therefore, the control informationcan be delivered reliably when the schedulable transmission block of theterminal changes temporarily or in a similar application scenario, whichreduces probability of data receiving errors of the terminal.

This embodiment is described by taking an example that a transmissioncontrol bit of a transmission block under invalid transmission controlindicates a transmission block to which the old belongs. Understandably,the transmission block to which the old data belongs may also beindicated by other control bits in the DCI format. That is, theinformation indicating the transmission block to which the old databelongs, where the old data is retransmitted by the transmission blockunder valid transmission control, may be written into control bits otherthan the transmission control bits in the DCI format.

FIG. 7 is a schematic structural diagram of a network side deviceaccording to an eighth embodiment of the present invention. As shown inFIG. 7, the network side device in this embodiment includes a controlinformation generating module 71 and a control information sendingmodule 72.

The control information generating module 71 is configured to setrespective control bits in a DCI format to generate control informationapplied by a network side to a terminal, where the control bits includevalidity indication bits and transmission control bits, indicationinformation indicating whether transmission control exercised by thenetwork side on a transmission block is valid relative to the terminalis written into the validity indication bits, and the validityindication bits are located outside the transmission control bits; and

The control information sending module 72 is configured to send thegenerated control information to the terminal.

In this scenario, the network side device in this embodimentpredetermines the validity indication bits in the DCI format of thecontrol information, and writes into the validity indication bits theindication information indicating whether the transmission controlexercised by the network side on the transmission block is validrelative to the terminal, which saves a resource overhead required to beoccupied. The saved overhead may be used for transmitting other controlinformation. Therefore, efficiency of using the overhead required fortransmitting the control information on the network side is improved. Animplementation entity of the network side device in this embodiment isnot limited, and may be a base station or an access network node.Reference may be made to the description about the embodiments shown inFIG. 1a , and FIG. 4a to FIG. 6 for its implementation mechanism, whichis not repeatedly described here.

Alternatively, in the network side device in this embodiment, thecontrol information generating module 71 may be configured to setrespective control bits in a DCI format to generate control informationapplied by a network side to a terminal, where control information otherthan indication information indicating whether to swap a correspondingrelationship between a transmission block and a codeword is written intoa control bit into which the indication information indicating whetherto swap a corresponding relationship between a transmission block and acodeword is originally written (namely, a “TB to CW swap flag” controlbit), and the control bit is in the DCI format, if a dedicateddemodulation reference signal used to demodulate data is preconfiguredby the network side for the terminal and respective codewords correspondto the same number of layers.

The control information sending module 72 may be configured to send thegenerated control information to the terminal.

In this scenario, the network side device in this embodiment determinesa function of the “TB to CW swap flag” control bit with reference to acurrent transmission status of the transmission block. If the indicationinformation indicating whether to swap a corresponding relationshipbetween a transmission block and a codeword is meaningless redundantindication information in the current transmission status, the controlinformation other than the indication information indicating whether toswap a corresponding relationship between a transmission block and acodeword may be written into the “TB to CW swap flag” control bit, whichsaves a resource overhead required to be occupied for transmitting othercontrol information, and improves efficiency of using an overheadrequired for transmitting the control information on the network side.An implementation entity of the network side device in this embodimentis not limited, and may be a base station or an access network node.Reference may be made to the description about the embodiments shown inFIG. 2a , and FIG. 4a to FIG. 6 for its implementation mechanism, whichis not repeatedly described here.

FIG. 8 is a schematic structural diagram of a terminal side deviceaccording to a ninth embodiment of the present invention. As shown inFIG. 8, the terminal side device in this embodiment includes a controlinformation receiving module 81 and a control information resolvingmodule 82.

The control information receiving module 81 is configured to receivecontrol information sent by a network side, where control bits of a DCIformat of the control information include validity indication bits andtransmission control bits, and the validity indication bits are locatedoutside the transmission control bits; and

The control bit resolving module 82 is configured to obtain, from thevalidity indication bits, indication information indicating whethertransmission control exercised by the network side on a transmissionblock is valid relative to a current terminal.

In this scenario, by detecting one bit of the validity indication bitsin the DCI format, the terminal side device in this embodiment mayobtain the indication information indicating whether the controlexercised by the network side on a transmission block is valid relativeto the current terminal, which saves a resource overhead required to beoccupied by the indication indicating whether the transmission controlon the transmission block is valid. The saved overhead may be used fortransmitting other control information. Therefore, efficiency of usingan overhead required for transmitting the control information on thenetwork side is improved, and efficiency of obtaining downlink controlinformation by the terminal side is also improved. An implementationentity of the terminal side device in this embodiment is not limited,and may be a user equipment or a mobile phone. Reference may be made tothe description about the embodiments shown in FIG. 1b , and FIG. 4a toFIG. 6 for its implementation mechanism, which is not repeatedlydescribed here.

Alternatively, the control information receiving module 81 of theterminal side device in this embodiment is configured to receive thecontrol information sent by the network side.

The control bit resolving module 82 is configured to obtain controlinformation other than indication information indicating whether to swapa corresponding relationship between a transmission block and a codewordfrom a control bit into which the indication information indicatingwhether to swap a corresponding relationship between a transmissionblock and a codeword is originally written (namely, a “TB to CW swapflag” control bit), where the control bit is in a DCI format of thecontrol information, if a dedicated demodulation reference signal usedto demodulate data is preconfigured by the network side for a currentterminal and respective codewords correspond to the same number oflayers.

In this scenario, through the terminal side device in this embodiment,if the indication information indicating whether to swap a correspondingrelationship between a transmission block and a codeword is meaninglessredundant indication information in a current transmission status, thecontrol information other than the indication information indicatingwhether to swap a corresponding relationship between a transmissionblock and a codeword is written into the “TB to CW swap flag” controlbit. By detecting the “TB to CW swap flag” control bit, the currentterminal may obtain the control information other than the indicationinformation indicating whether to swap a corresponding relationshipbetween a transmission block and a codeword, which saves a resourceoverhead required to be occupied for transmitting other controlinformation, and improves efficiency of using an overhead required fortransmitting the control information on the network side. Animplementation entity of the network side device in this embodiment isnot limited, and may be a base station or an access network node.Reference may be made to the description about the embodiments shown inFIG. 2b , and FIG. 4a to FIG. 6 for its implementation mechanism, whichis not repeatedly described here.

FIG. 9 is a schematic structural diagram of a communication systemaccording to a tenth embodiment of the present invention. As shown inFIG. 9, the communication system in this embodiment includes a networkside device 91 and a terminal side device 92.

The network side device 91 is configured to: set respective control bitsin a DCI format to generate control information on the terminal sidedevice 92, where the respective control bits in the DCI format includevalidity indication bits and transmission control bits, indicationinformation indicating whether transmission control exercised by thenetwork side device 91 on a transmission block is valid relative to theterminal side device 92 is written into the validity indication bits,and the validity indication bits are located outside the transmissioncontrol bits; and send the generated control information to the terminalside device 92.

The terminal side device 92 is configured to: receive the controlinformation sent by the network side device 91; and obtain, from thevalidity indication bits in the DCI format of the control information,the indication information indicating whether the transmission controlexercised by the network side device 91 on the transmission block isvalid relative to the terminal side device 92.

Alternatively, the network side device 91 is configured to: setrespective control bits in a DCI format to generate control informationon the network side device 92, where control information other thanindication information indicating whether to swap a correspondingrelationship between a transmission block and a codeword is written intoa control bit into which the indication information indicating whetherto swap a corresponding relationship between a transmission block and acodeword is originally written (namely, a “TB to CW swap flag” controlbit), and the control bit is in the DCI format, if a dedicateddemodulation reference signal used to demodulate data is preconfiguredfor the terminal side device 92 and respective codewords correspond tothe same number of layers; send the generated control information to theterminal side device 92.

The terminal side device 92 is configured to: receive the controlinformation sent by the network side device 91, and obtain, from the “TBto CW swap flag” control bit in the DCI format of the controlinformation, the control information other than the indicationinformation indicating whether to swap a corresponding relationshipbetween a transmission block and a codeword.

In the communication system in the embodiment of the present invention,the network side device extends or changes functions of some controlbits in the DCI format of the control information, so as to improveefficiency of using a resource overhead occupied by the control bits inthe DCI format of the control information, and improve efficiency ofusing an overhead required for transmitting the control information.Reference may be made to the description about the embodiments shown inFIG. 1a to FIG. 6 for implementation mechanisms of the network sidedevice or terminal side device in the communication system, which arenot repeatedly described here.

It is understandable to those of ordinary skill in the art that theaccompanying drawing is only a schematic diagram of an embodiment, andthe modules or processes in the accompanying drawing are not necessarilyrequired for implementing the present invention.

It is understandable to those of ordinary skill in the art that themodules in an apparatus in an embodiment may be distributed in theapparatus in the embodiment according to the description of theembodiment, or may be located in one or more apparatuses different fromthe embodiment through corresponding changes. The modules in theforegoing embodiments may be combined into one module, and may also besplit into multiple submodules.

The sequence number of the foregoing embodiments of the presentinvention is for ease of description rather than representative of apreference order of the embodiments.

Persons of ordinary skill in the art should understand that all or partof the steps of the foregoing method embodiments may be implemented by aprogram instructing relevant hardware. The program may be stored in acomputer readable storage medium. When the program is executed, thesteps of the foregoing method embodiments are executed. The storagemedium may be any medium that may store program codes, such as a ROM, aRAM, a magnetic disk, or an optical disk.

Finally, it should be noted that the foregoing embodiments are merelyprovided for describing the technical solutions of the presentinvention, but not intended to limit the present invention. Although thepresent invention is described in detail with reference to the foregoingembodiments, it is apparent that persons of ordinary skill in the artmay still make various modifications to the technical solutions recordedin the foregoing embodiments, or make equivalent replacements to part ofthe technical features of the technical solutions recorded in theforegoing embodiments; however, these modifications or replacements donot make the corresponding technical solutions depart from the spiritand scope of the technical solutions of the embodiments of the presentinvention.

What is claimed is:
 1. A method for receiving control information, comprising: receiving control information having one of a first downlink control information (DCI) format and a second DCI format; and obtaining control bits from the received control information; wherein: the first DCI format contains a transmission block to codeword swap flag control bit field for a terminal if a dedicated demodulation reference signal used to demodulate data is not preconfigured by the base station for the terminal; and the second DCI format does not contain the transmission block to codeword swap flag control bit field for the terminal if the dedicated demodulation reference signal used to demodulate data is preconfigured by the base station for the terminal.
 2. The method according to claim 2, wherein the transmission block to codeword swap flag control bit field carries indication information indicating whether to swap a corresponding relationship between a transmission block and a codeword.
 3. The method according to claim 2, wherein if a value of the transmission block to codeword swap flag control bit field is 0, the transmission block to codeword swap flag control bit field indicates that a transmission block 1 corresponds to a codeword 0 and a transmission block 2 corresponds to a codeword 1; and if the value of the transmission block to codeword swap flag control bit field is 1, the transmission block to codeword swap flag control bit field indicates that the transmission block 2 corresponds to the codeword 0 and the transmission block 1 corresponds to the codeword
 1. 